The present invention relates to bar codes, and deals more particularly with encoding an additional layer of information in a conventional one-dimensional bar code symbology.
Existing 1-dimensional (hereinafter, “1-D”) bar codes provide a limited amount of information. Furthermore, that information is limited to specific sets of characters. Depending on the bar code symbology that is used, the allowable character set may vary, but as a maximum the allowable characters are limited to the base ASCII character set. (The term “bar code symbology” refers to a predetermined manner in which bar codes encode alphanumeric text.)
Changing the bar code encodings to allow more information to be encoded requires new symbologies, and widespread changes throughout industry because of the number of existing 1-D bar code scanners with integrated firmware in use throughout the world that would not be able to read the changed encoding. Accordingly, requiring that all existing 1-D scanners are replaced with new scanners would result in significant expense.
Techniques are known for encoding additional information in 1-D bar codes by using color printing. However, use of color impacts the printing of legacy bar code labels. Most legacy bar code printers use either thermal printing or thermal transfer printing, both of which are monochrome. Bar codes may be printed on demand, or preprinted on labels. In either case, changing artwork to support multiple colors would have significant cost impacts. Some existing bar code scanners designed for monochrome may have difficulty determining bars and spaces due to the varying contrast ratio of the colored bars, which may make it necessary to replace the existing bar code scanners with ones that support decoding (i.e., reading) of labels printed in color, again implying a significant expense.